Aiea (Hawaiian: ʻAiea) is a census-designated place (CDP) located in the City and County of Honolulu, Hawaii, United States. As of the 2010 Census, the CDP had a total population of 9,338.
Aiea is located at 21°23′9″N 157°55′51″W (21.385900, −157.930927). According to the United States Census Bureau, the CDP has a total area of 1.8 square miles (4.7 km2), of which, 1.6 square miles (4.1 km2) of it is land and 0.1 square miles (0.26 km2) of it (5.71%) is water.
Kamehameha Highway (Hawaii Route 99) divides most of Aiea from the shore of Pearl Harbor (mostly US government property), and the parallel major thoroughfare, Interstate H-1, further cuts the town's commercial district into two distinct areas. These east-west routes (and other streets, such as Moanalua Road) connect Aiea to Pearl City, immediately adjacent on the west, and Halawa, adjacent on the east. The residential area known as Aiea Heights extends up the ridgeline above the town. The communities of Newtown Estates and Royal Summit are located at the western edge of Aiea near its border with Pearl City at Kaahumanu Street. Residents of the census-designated places (CDP) of Waimalu and Hālawa use Aiea in their postal address.
"ʻAiea" was originally the name of an ahupuaʻa, or Hawaiian land division. The name was derived from a species of plant in the nightshade family, Nothocestrum latifolium. It stretched from ʻAiea Bay (part of Pearl Harbor) into the mountains to the north.